After freezing up early this afternoon, Twitter is starting to thaw out as frustrated users tweet about the downtime.

At about 3:30 p.m. Eastern time today, Twitter Inc. updated users on its status page with a notice saying that the problem that stymied Twitterers for a few hours today was repaired.

At 1:50 p.m., Twitter had told users that tweets were not reaching the followers of Twitterers and that engineers were starting to deploy fixes. By 3 p.m., many users were reporting that their service was back up and running and that their tweets were no longer frozen.

The Twitter woes started between 10 a.m. and 11 a.m. Eastern time. Users could post tweets, which would be published on their own stream, but updates from followers weren't showing up on their streams.

Twitter has not disclosed what caused the problem. The microblogging company did not respond to a request for comment but noted on its Web site that engineers were deploying fixes.

Once tweets started moving again, users were quick to vent their frustration with the lack of service.

"'twitter is frozen...' feels weird!! PRE-FRIENDS days... none of you will get this, but it's WAY TO QUIET in my world!!!! miss you all...," wrote one Twitterer. Another tweeted, "Twitter Is Frozen, which means right now, in offices all around the world, stuff is actually getting done."

Another tweet read, "Twitter was frozen in time. Really weird. I stared at my own updates for 3 hrs." And another said, "Twitter is frozen and y'all bout to lose ya minds. I'd hate to see what y'all would do if Twitter shuts down for good."